This is what my company says about the logging of PICUS hours:
PICUS is flighttime as pic under supervision. The objective of PICUS hours is to perform the required PIC hours to obtain your ATPL (A).
If you want to log a flight as PICUS:
- Inform the PIC before the briefing at the start of your flight that you want to log as PICUS. This gives the PIC the oppurtunity to evaluate your overall performance from beginning till end. Before signing of the PICUS flight.
- You have the perform at such a level as PICUS that the PIC does not have to intervene at any stage during the flight.
- The PICUS hours need to be signed of at the end of the flight by the PIC.